GameSpot readers know what they like – and they know what they don’t like.

Owned and operated by CBS Interactive, the video game news and reviews site caters to the mainstream console gamer aged 18 to 40. And they’re an opinionated, assorted bunch.

“On the surface level, that might seem like a homogenous audience – simply gamers – but when you get deeper into it, it’s actually very diversified,” said Nick Edwards, CEO of Boomtrain, a personalization platform that uses machine learning to deliver targeted content based on user behavior and desired channel.

Boomtrain, which works with CBSi, a division of CBS Corporation, announced $12 million in Series A funding on Tuesday from Sierra Venture, Cota Capital and Lerer Ventures, bringing the San Francisco-based company’s total funding to $13.97 million since it was founded in 2012.

The bulk of the money will go toward a combination of platform development and hiring. Edwards said Boomtrain, whose other clients include The Guardian, Thrillist Media Group and UK broadcaster Sky, is looking to increase headcount from 40 to to around 55 by the end of the year, with plans to double that number throughout 2016. Most of those new hires will be in engineering and data science roles.

For the moment, Boomtrain’s sweet spot is personalized email, although it’s already started scaling up its efforts on the web, in apps and via mobile push. CBSi uses Boomtrain to personalize and automate its email marketing efforts for GameSpot.

“Email is far from dead with our demographic,” said Michael Powers, SVP and general manager of CBSi Games. “Email subscribers make up our most engagement audience segment.”

GameSpot uses Boomtrain to send individually tailored emails to roughly 2 million subscribers, said Powers, who noted that GameSpot has upped its sending pace to three times a week since starting up Boomtrain, with users becoming two to three times more likely to visit the site after engaging with recommended content.

The site is also in the beginning phases of a project to use Boomtrain’s tech to personalize the web experience on GameSpot.com and cross-promote visitors across CBSi’s other gaming properties, including Giant Bomb, GameFAQs and ComicVine.

Boomtrain’s platform collects first-party data by tracking users across its clients’ websites to build individual customer profiles and determine preferences based on behavior.’

From there, it’s a matter of targeting content based off of those profiles. Boomtrain creates dynamic buckets of multiple pieces of content designed to appeal to specific users. When those users take an action – say, they open an email – Boomtrain serves up a piece or several pieces of content from the bucket.

Boomtrain’s algorithm also has what Edwards called “the notion of serendipity” built in. Every so often, users are presented with a random but semi-related piece of content to help users expand their worldview.

“One thing we don’t want to do is to always show people things they’ve already seen before or give them echoes of what they’ve already done,” Edwards said.

Which wouldn’t fly with the GameSpot audience, a tech-savvy, demanding and vocal group that isn’t shy about calling foul on inauthentic experiences, said Powers.

“The new normal for our audience are sites like Facebook, LinkedIn and Netflix, where the experiences are individually tailored with personalized content,” he said.

Publishers also have to keep the bottom line firmly in mind. GameSpot also leverages Boomtrain’s analytics product to tap into trends and audience reading habits.

“Creating content is costly and time-consuming, and we are publishing more than ever in our history,” Powers said. “So being able to laser target the audience segments that are most likely to engage is crucial.”